Party-line telephone exchange



Aug. 25, 1925. 1,551,263

1 N. E. NORSTROM PARTY LINE TELEPHONE EXCHANGE Filed Sept. 6, 1921 4 Sheets-Sheet 1 N. E. NORSTROM V PARTY LINE TELEPHONE EXCHANGE Filed Sept. 6, 1921 4 Sheets-Sheet 2 Aug" 25, 1925.

N. E. NORSTROM PARTY LINE TELEPHONE EXCHANGE Filed Sept. 6, 1921 4 Sheets-Sheet 5 Wp'zea 696 x 1,551,263 N. E. NORSTROM PARTY LINE TELEPHONE EXCHANGE Filed Sept. 6, 1921 4 Sheets-Sheet 4 Patented Aug. 25, 1925.

NIns E. Noasa'aan, or tarmac, irairiwo rs.

PARTY-mun iELErHoNE tiXoHA'NeE.

Applia'tionrfiled SptembeFG, 1921. Serial no. 498168 9 ToaZZ whom "it may concern:

Be 'it known that I, Nrns E. NoRs'rRoM, a citizen of the United States of America, and a resident of Chicago, county of Cook and State of Illinois, have invented certain new and useful Improvements'in PartyaLine Telephone Exchanges, of which the following is a specification.

My invention relates to party line "telephone exchanges, and has forits object improvements in such exchanges.

In the accompanying -dr-awings Fig; 1 is a plan of -a part of the central office mechanism; 7

Fig. 2is a side elevation of thesame;

Fig. '3 is ,a sectional elevation on line 33 of Fig. 1;

Fig. 4 is an enlarged section on line 4-4 of Fig. 3; a j

Figs. 5 and "6 are similar sections with the parts in slightly different ipositions; V

Fig. 7 is a section online 7- 7 of Fig.1;

Fig. 8 is a section 011311116 8"-8 of "Fig. 7

Figs. 9 and 10 are elevationsof contact.

springs shown to the-right in Fig. "1;

Fig. 11 isa diagram of the centraloffice apparatus anda part of one partyrline-extending therefrom;-and

Fig. 12 is a condenseddiagramof one of the local stations.

Supported on a bed 11 are standards 12, 13and 14. I-n-the standard 12'is a shaft 15 which has a cam 16 on one endj-a'nda worm gear 17 on the other end. A constantly running worm 18 engages the gear 17.,t0 'keep it constantly running. standard 19'are two s'etsof contact springs which have their electrical connections shifted back and forth hythecam l6once during each revolution of the shaft "15. This operation will he explained more full-y in connection with'the description of th'ecircuits. i

Supported inthe standard 13 is a shaft which has a disk :20 on one end, andin the face of this disk near its periphery isa series of equally spaced holes 21. Atrain ofigears 22 connects the shaft of -disk20 with the shaft 15 so ithatthe said disk is also "constantly driven. This gearing is so'a'rran'g'ed that during thetime when the shaft :15is making one'complete revolution, the diskr2O Supported on a. j

,hole 21 1n d sk 20.reg1sters w1tl1'the pin 39, {the spring 41 projects said pin into such moves the distance between .one hole2'21 and the next adjacent one.

Secured to the standard by screws 22 and 23 '(Fig. 3 is a metal plate 24, and secured to this plate'by screws, 23, 25 and 26 is an arc-shaped piece a of, insulation. 27 .in

. ranged to" both turn and slide in its hearing in"said standard. Onthis shaftris an arm '32, and 011 this arm isa pin 33 adapted to engagefthe stop .pin 30. ()n the shaft 31 is a spring 34 which serves to hold the arm- 32 withthe pin 33 in contact. with pin 30, and also to hold the shaft 31 to the left as seen in Figs. 1 and 2. On thebe'd 11 is a magnet 35 provided with an armature *36 arranged to strike an, adjustable nut 1or -colwhich-are contact pins '28. On the standard 1 lar37 on shaft 31 and move said-shaft lon- I .gitudinally when the magnetis energized.

.Secured on the arm .32,is-a-'socket 38in which is a pin 39 which is in linewith rthe' holes 21 in disk 20. When innormaliposition the parts are as shown in Fig.4 and in full lines in Fig. 8. When the magnet'35 .attracts its armature,- the shaft 31 and arm '32 are moved to the right as "seen in Figs.

land 2. This bringsthepin 33 against a small block40 (Fig.8) which is'secured to arm 29 under .pin '30. It also brings the end of pin39 against the face of the con-v stantly rotating disk 20 to slightly deflect spring 41 as shown in Fig.5. As soon as a hole, and thereafter the-arm 32turns with the disk :20. "Injthiscondition the pin '33 (Fig. 8) 'moves downward on-the face of block 40, and as soon as it reachesthe'lower edge of said block; th'eupants vmo'vei'from the full line to the dotted line Epos'ition. This movement .isunder the actionof the'm'agnet The parts in Fig. "6 correspond to the dotted line positions'hown in Fig- 8.

35 which keeps a longitudinallstrain on shaft 31 duringthis movement 0f arm 32.

40 shifts the electrical connections of the other springs. This matter will be further described in connection with the operation.

On the arm 32 is an insulated contact maker or wiper 42 arranged to make contact with-pins 28 when the arm is rotated in the manner described' The pins 28 are twice as numerous, within the space occupied by them, as the holes 21 in disk 20.

In other words, the wiper 42 engages two pins 28 during the time the disk is moving I the distance equal to that between one hole 21 and the next adjacent one.

At the right in Figs. 1 and 2 are some contact springs shown in elevation in Figs. 9 and 10.- These springs are operated back and forth once during each revolution of shaft 15. This will befurther described in connection withthe description of the operation.

In addition to the apparatus described,

there are at the central office a series of keys used inmaking calls on apartyline,"a series of magnets controlled by the keys, cord circu ts, and generators. Also, at the central ofiice, in connectionwith each partyline,

are 'a'jack, a' drop and a mechanism which operates synchronously with the mechanisms at the local stations on the line. These last are substantially the same as those shown in my former Patent No.1,326,-

1 dated December 30, 1919. The slight ence between the previous mechanism associated with each party and the present one will be set forth in the description of he A party line may have any of local stations thereon, and the otiice apparatus will include cons for all of these stations. In Fig. 1 have shown connections for stations, it being understood that I cc nections of the same kind, and con- -to:l in the same way, are used for addinal stations. j

wil be assumed that the operator at entral office wishes to call the sub- 3 station No; 2, illustrated arbiby a circle in the upper partof Fig. e begins by inserting the plug L4 thejack of the line wanted, by pressing and by pressing the key B onher keyboard which would correspond'to station No. 2. A current then flows as follows: generator Xi5--4647relay 48 19 The consequent operation of relay A shifts the adjacent springs, one part of which consists in this relay closing a branch circuit for itself independent of key 13 as follows :61 68697 O-71-6667 X.

The operation of the relay 18 shifts its adjacent springs, one effect of which is to close a branch circuit as follows 1-772 7374 l'amp 75'-65-66-67X.

Another effect of the operation of relay 48 is to connect the generator X to one side of the party line, whereupon a current flows as follows :Xi57 677ground to all of the local stations on the line787980 which is in a' shunt around the magnet 35. I

This puts the magnet 35 in series withthe relays 48 and A from the wire 52 to the.

wire 59. The consequent operation ofmagnet 35 moves the shaft 31 (Figs. 1 and 2) a short distance to break the electrical con-' nection between springs 53 and 54:, but not between the other adjacent springs. This is a second break in the shunt around magnet 35 and provides that the circuit for that magnet will not be affected when it is broken thru relay 89 at springs 76 and 92.

The preliminary movement of the shaft 31 is quickly followed by a hole 21 in disk 20 coming opposite the pin 39 carried on the arm 32. hen this occurs the arm 32 is car ried with the disk 20 until the pin 33 slips from contact with the block 40. Upon the occurrence of this action the shaft 31 is moved longitudinally to shift spring 86 from p 87 to 95, whereupon impulses flow as fol- These are impulses in the operating or stepping up direction and serve to advance the various switching mechanism from their normal positions.

From the above it will be seen that the v shift from impulses in the release direction to impulses 1n the stepping up direction occurs when the shaft 31 makes its final moveine'nt under 'the 'actien of magnet as a. 'res'ultof 33 sli'ppingtromblock 40. The

,wip'er 42 iss'o set that it engagesthe 'first pin 28. just jatfter the fourth stepping up impulse. In other words, the first three of these impulses are idle and the "fourth becomes the first as far as operating is concerned. This is for the purpose ofaccommodating details of local station apparatus which are not herein described becausethey have no bearing on the present invention. The pins 28 are so arranged that the first two correspond to the relay A and conse qi'iently to; station No. 1 on the line. The next two pins 28 correspond to relay A and station No. 2and so on.

Then the wiper 42 engages the upper pin 28 of the first pair, nothing occurs as the connection to that pin isjopen'by reason of the relay 'A not being operated. When the wiperengagesthe lower pinof'the first pair, nothing occurs because the connection is open at the lower spring of relay A by reason of that relay having been operated as a consequence of depressing'key B When the wiper 42- reaches the upper pin of the pair associated with A and B a current flows: -X- 45 4e 47 1 -e1a 10e 107 108%109 '110- 111- 112 42- 11371-- 66'-67'X. I I r Normally the springs96 and 97 connect the tip "and sleeve sides of the cord together after the relay 48 has operated, and consequently connecttegether electrically the two limbs of the line reaching the localstation. When the relay 106 operates it cuts "this shunt by epening springs 96 97. In this operation the spring 97 connects ground to the sleeve side of the cord, and this occurs when the generator X has its negative side connected to ground. Under these condi tions a current flows :1-X45'76-93-94 86 8584-S3-82818079 78- local station No. '2 (which is the one having its mechanism set for the second operating impulse) 104 10210110099 98 97 '97* grouncl 105 92 67 X. This is" an impulse thruthe cut-in coil of the selected station and serves to connect that station'telephonically to the line in the manner well known in the art.

1 By comparing the circuit just given thru the cut-in coil of the localstation with the previously given circuit thru the operating coil it will be seen that the two are thesame except that the operating impulse "goes to ground at the local station whereas the cutin impulse goes back over the wire 104 and reaches ground at spring 97. In other words, the stepping up magnetand'tlie cutin coil of the local station, are in parallel in a circuit closed by the cam 16, the branch including the chitin coil being closed by the relay106fwlienthe wiper 42 engages the first pin associated with the relay A This is the second pin of thesecond pair, the line 7 is open at spring by reason of theaction of relay A shifting its springs. 'Butthere is a connection 116 extending. from spring 115 to the spring 117 associated with relay A which spring is in contact with spring 118 when A has not been operated. The wire 116 corresponds 'to the wire 120 which connects'spr'ing 119 of relay A with spring 121 of relay A "Si1'nilarly,there is a wire 122 which extends to'a springon the next relay (which would be 14 that corresponds to the springs 119, 115 and 117. In the same way connections'are made step by step 'thru correspondingsp'rings for as many relays as are used'in the arrangement.

From the corresponding s'pring'of the last relay there is a connection 125 torelay 124. As only three relays A are shown this wire extends from connection 126. Consequently, when the wiper reaches the pm 114, which is the second pin ofthe second pair, a cur- The actuation of relay 124breaks the connectionbetween springs 50 and 51, which is M in "the circuit for n1agnets48, AZ-and 35, thereby permitting their armatures'to fall back to normal positions.

When the armature of A falls back "it breaks the circuit for 106 at spring. 109.

hen the "armature of 'magnet35 falls back it permits the arm 32 to be freedfroni the disk 20 so that spring 34 may return these parts to normal position. This action breaks the circuit for 124 at the contact pin 114.

This leaves the selected station No. 2 con nected to the cord, and "all'electrically operated devices at the central oflice in their normal positions.

When the arm'ature of 48 falls back, it con nects'the ringing generator G to the ringing commons 82and 101 thru "connections readily traced. As the operator is presumed to havethe key K depressed at thistime, ringing current flows over line limbs 78 and 104 to station No. 2.

it is'desired to connect stations land 3 to the line-atthe same time by reason of the fact that the subscriber at one of these stations wishesto talk to the subscriber at the other. The operator inserts the plug 44 and *presses thekey'K as'before. 'Sheialso presses keys B and B representing stations Nos. 1

6667-X. Also a branch from 60A the same as described before until the wiper 42 engages the first pin. hen this occurs, a current flows X4 546-'47 -106-107 184 135 136 137 13842-11371 This connects spring 97 to groundso that an impulse flows over the two limbs of the line tofoperate the cut-in coil at station No. 1 and connect that station telephonically to the line. When the wiper 42 engages the second pin, the connection therefrom which,

goes thru 120, 115 and 116 is found open at 117 because pressing key B caused A to shift its springs. Consequently nothing happens when the wiper engages the second pin. Also,nothing happens when the wiper engages pins 112 and 114 as will be readily seen by remembering that A has not been operated and A has.

hen the wiper 42 engages pin 123, another impulse flows thru relay 106 as before, except that it goes by the way of the springs of A instead of by the way of springs of A or A As before, the efiect is to send an impulse thru the cut-in coil of station No. 3 to connect that station telephonically to the line. V

lVhen the wiper reaches pin 39, which is the second pin associated with the highest numbered station, an impulse flows as be fore thru 124 which in turn breaks the circuit thru 48, A and 85, and results in connecting generator G to the line.

By referring back to the previous descrlptions it will be seen that when the operator depresses any key B, a circuit is closed'thru the relay 48 and thru the particular relay.

A which corresponds to the key B depressed. The actuation of the relay 48 closes a branch of this circuit thru the lamp 7 5.

This branch remains closed as long as a.

current flows thru relay 48, and such current contlnues to flow as long as a key B is depressed except for the break accomplished by the subsequent action of relay 124. Consequently, the burning of the lamp indicates that a key B is depressed.

While the current is flowing steadily thru relay 48 and lamp 75 in parallel, release and operating impulses flow thru another branch from the same source and find ground at a plurality of stations. The source X and the resistances in the various branches are so related to each other that each impulse thru the magnets of the local stations draws on the lamp 75. As a consequence, the flickering of the lamp shows'to the operator that the system is operating properly. \Vhen finally the. branch circuit thru lamp 7' 5 is broken by reason of the armature of 48 fall ing back the lamp goes out and the operator releases the depressed key B.

As previously stated, release and stepping up (operating) impulses which go thru the local stations also go thru the magnet 193. Stepping up impulses thru this magnet advance theratchet wheel 140 step by step. ()n the shaft of the wheel140 is a cam 141 which acts to shift a spring 142 from contact 143 to contact 144 when the wheelis the pallet but which move beyond that arm Y when the wheel is advanced. WV hen release impulses flow thru magnet 193, the first i1npulse permits the wheel-to return until the first-projection engages the pallet. The second impulse permits it to return until the second projection engages the pallet, and the third impulse releases the second projection. In other words, it requires-three release impulses to fully release this apparatus, which differs from the apparatus at the local stations in that those do not have the projections 146 and are normally'fully released by a single release impulse.

WVhen the subscriber is thru talking he slgnals the central oilice 1n the ordlnary manner, and the operator removes the plug 44. Thereupon an impulse flows :X45

76-77ground to all local stations on the line and to magnet 193-7 87 9147-142 14490.919267X.

This is an impulse in the release direction and permits the apparatus at the several stations to returnto normal position. But the wheel 140 does not fully return to normal by a single impulse by reason of the projections 146, and spring 142 is held againstcontact 144 by cam 141 until such return is complete. As a result, another release impulse is sent each time that the shaft 15 makes a revolution until the release is complete.

Normally, the apparatus at the local stations is completely released by a single release impulse, but the best apparatus will sometimes get stuck for some reason or other and can be released by repeated jarring or by taking it apart to see what the trouble is. These repeated release impulses are for the purpose of insuring complete release in case a single release impulse should fail to acessees complish that result. The release impulses which are first sent out when a keyB is; de{ pressed are also for. the purpose of. making certain, that all. appaigatusis at normal; posi tion before stepping up begins.

"I A. This starts the previously described operations which lead; to the wiper 42 engaging the pins28. After pressing the last key 13 and before the wiper 42 begins making its contacts, she presses the key G which closes a readily traceable branch circuit for the relay 1-06. This connects 97 to ground so that when the wiper 42 engages the second pin of each pair a cut-inv impulse flows thru the cut-in coil of thecorresponding station so as to connect all stations telephonically to the line. She holds. key C depressed until the light goes. out.

lVhen the operator later returns, she presses the release key R which closes acircuit thru relay 48 without closing it thru any station controlling relay. This circuit is as follow X45-46--47-.4'849505 1-. 148149.150'6465-66 67 X. The effect of the actuation of 48 is as before to. send a series of release impulses thru the local stations. This time, however, the re.- lease impulses are not followed byv stepping up impulses because the branch which goes.

thru the magnetis not closed by depressing some key B.

On the keyboard is a key. M which is, shown without electrical connections. This is a key for starting the generator X, the details of the circuit of which are, not material to the present invention. I

Referring back to Fig. 8 it will be seen that the pins. 30. and 33 have beveled ends. When the shaft 31 is moved axially to lo'ck; the arm 32 to the constantly revolving disk 20, the pin. 33 is moved away in the arc of a circle from the pin 30, but is not moved away axially. After the required stepping up impulses are completed, the circuit is broken thru magnet 35 and spring 34 moves the shaft 31 back to free the arm 32 from the disk 20. But if for some reason the parts get stuck and the spring 34 fails to release arm 32, then the pin 33 will continue to travel in a circle until the bevel on pin 33 strikes that on the stationary pin 30. whereupon the wedge action of one upon the other will mechanically force the shaft 31 backward to release arm 32.

As previously stated, the two limbs of the line are connected together between the time the relay 48 operates and the time the relay: 1(96 to, connect for a cut-in @011. As a v con sequence, if." any,- not wanted subscriber. should; operate. his generator during, the time his apparatus was going oyerhisfcut-in con tact, the .currentfroinl' the: generator. would not operate his cut-incoil because the conai ntavaen the linelimbsmakes a. Sliiint. which prevaaseuch o oenatio n W'Vhfatl I unms;

1. line, system, a line having. a plurality of stations connected. thereto, a.

plug. and ja ck by which the "linel is connect ed; to a central office, means fonsending op: erating. and release mpulses over the line to control thetelephoneconnections ofthe star, 7

isiif h sf fi id e t eti l y p rate means wh ch a: plurality. of release impulses. are; caused to, flow.- over the line. when the plugfisreinoved from, thefj'aok. l An, apparatus. arrangedto. hejadvanced step by steo byiinpulses flowing in ease-i, rection and to, be released by." niiu flowing in the opposite directiomand by which. upon the apparatusnot been; fully released by. one release impulse c release impulses will automatically-contto flow until such release is complete. 3. An apparatus arranged to be advanced step by step from, normal position by elec trical impulses in o ie directicnand to be released by. impulsesin the opposite direction, means for sending a series of release impulses. and automatically operating;

means which such impulses are inter-- rupted wheirtlie apparatus reaches norzna position. 7 e i r I 4. In a telephone exchange, a party connected to. a central officeymeans for send-o ing impulses over the line to operatedevices at local stations thereon, an electrical de viceoperate'd after the initiation of said impulsesto, cause a: special impulse serving to connect a selected station telenhonically, to the line. and means by which the. two limbs ofthe line are held in electrical connection with each other during the intervaljbetween the in tlation Of Sa-Id impulsesand the operation of sald electrlcal devlce.

5. The combination/with a central oiiice, a

party line having stations thereon, and a source of electrical impulses, of'means for connecting the two limbs of the line together at the central office and for connecting said source to one of said limbs so that impulses may flow through the stations on said line, and means by which upon disconnecting the line limbs at the central oflice an impulse will flow through another part of one of said stations to connect ittelephonically to the line.

6. The combination with a party line having a series of local stations thereon, a source of electric current, and means for closing for a successive number oftimesa circuit having branches through the several stations, of means for closing a second branch of said circuit through a selected one of said'stations during the time the circuit is closed through all of them.

7. A party line connected to a central oifice, a source of electric current, devices for sending a series of impulses over said line and through the stationsthereon, a lamp located in a separate circuit and lighted when such impulses begin and extinguished when they cease, and means by which the correct operation of said devices is indicated by fluctuations in the light from said lamp.

8. In a telephone exchange, .a source of electricity, a lamp, electrical devices at local stations on a party line, a circuit from said source and having branches through said lamp and said stations, and an interrupter,

in the branch leading to the stations said parts being soarranged that the operation of the interrupter affects the quantity of current flowing thru the lamp without interrupting the same.

9. The combination with a central office, a party line connected thereto, and asource of electricity, of a constantly running body, a contact maker, means for 'moving said contact maker to engagement with said body and into a path in which it will make electrical connections, means by which impulses.

from said source will flow over said line in a release direction when the contact maker is first moved, and means by'which the impulses from the source will be changed to a stepping up direction over said line when the contact maker reaches said path.

10. The combination with a party line, a central office, and a source of electricity, of a contactmaker, a magnet arranged when actuated to start a series of mechanical operations one of which consists in moving said contact maker over a series of stationary contacts, and means controlled through said contact maker and one of its stationary c011- tacts for breaking the circuit for said i'nagnet to stop said series of operations.

11- Ina controllingmeclranism for send-.

ing impulses over a party line, a continuously operatlng devl'ce arranged to make and break electrical connection at regular intervals of time, a disk geared to said device so as also to be continuously moved, said disk having connecting points, a normally idle contact maker, and means for connecting said contact maker to one of said connecting points so as to move it.

12. A device arranged to continuously make and break electrical connections, a perforated disk connected to said device so that the disk will move the distance between one perforation and the next while the device is making one cycle of operations, a normally idle contact maker, and means for connecting said contact maker to said disk at one of said perforations.

13. The combination with a party line, a device for sending electrical impulses over said line at regular intervals, and means for connecting said device to said line, of a normally inactive device arranged upon actuation to send secondary impulses over said line, and automatically operating means for connecting the normally inactive device in a definite relationship to the first mentioned device.

14. The combination with a party line, and a device for sending electrical impulses over said line, of two sets of contact springs each set having a normal relationship, a magnet arranged upon actuation to change the normal relationship of said springs, means by which said device controls the actuation of said magnet so as to cause the magnet, means actuated by the sending device for controlling said magnet so as to cause the two sets of springs to be actuated lat difierent times, and means by which the actuation of the second set of springs operates to change the impulses sent by said device.

NTILS E. NORSTROM. 

